1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (c) by Lee Revell <rlrevell@joe-job.com> 4 * Clemens Ladisch <clemens@ladisch.de> 5 * Routines for control of EMU10K1 chips 6 * 7 * BUGS: 8 * -- 9 * 10 * TODO: 11 * -- 12 */ 13 14 #include <linux/time.h> 15 #include <sound/core.h> 16 #include <sound/emu10k1.h> 17 18 static int snd_emu10k1_timer_start(struct snd_timer *timer) 19 { 20 struct snd_emu10k1 *emu; 21 unsigned int delay; 22 23 emu = snd_timer_chip(timer); 24 delay = timer->sticks - 1; 25 if (delay < 5 ) /* minimum time is 5 ticks */ 26 delay = 5; 27 snd_emu10k1_intr_enable(emu, INTE_INTERVALTIMERENB); 28 outw(delay & TIMER_RATE_MASK, emu->port + TIMER); 29 return 0; 30 } 31 32 static int snd_emu10k1_timer_stop(struct snd_timer *timer) 33 { 34 struct snd_emu10k1 *emu; 35 36 emu = snd_timer_chip(timer); 37 snd_emu10k1_intr_disable(emu, INTE_INTERVALTIMERENB); 38 return 0; 39 } 40 41 static int snd_emu10k1_timer_precise_resolution(struct snd_timer *timer, 42 unsigned long *num, unsigned long *den) 43 { 44 *num = 1; 45 *den = 48000; 46 return 0; 47 } 48 49 static const struct snd_timer_hardware snd_emu10k1_timer_hw = { 50 .flags = SNDRV_TIMER_HW_AUTO, 51 .resolution = 20833, /* 1 sample @ 48KHZ = 20.833...us */ 52 .ticks = 1024, 53 .start = snd_emu10k1_timer_start, 54 .stop = snd_emu10k1_timer_stop, 55 .precise_resolution = snd_emu10k1_timer_precise_resolution, 56 }; 57 58 int snd_emu10k1_timer(struct snd_emu10k1 *emu, int device) 59 { 60 struct snd_timer *timer = NULL; 61 struct snd_timer_id tid; 62 int err; 63 64 tid.dev_class = SNDRV_TIMER_CLASS_CARD; 65 tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE; 66 tid.card = emu->card->number; 67 tid.device = device; 68 tid.subdevice = 0; 69 err = snd_timer_new(emu->card, "EMU10K1", &tid, &timer); 70 if (err >= 0) { 71 strcpy(timer->name, "EMU10K1 timer"); 72 timer->private_data = emu; 73 timer->hw = snd_emu10k1_timer_hw; 74 } 75 emu->timer = timer; 76 return err; 77 } 78